diff --git a/libs/ardour/surround_return.cc b/libs/ardour/surround_return.cc
index 4ed375ec06..d642d83864 100644
--- a/libs/ardour/surround_return.cc
+++ b/libs/ardour/surround_return.cc
@@ -175,7 +175,7 @@ SurroundReturn::SurroundReturn (Session& s, Route* r)
 		UInt32 renderingAlgorithm = 7; // kSpatializationAlgorithm_UseOutputType;
 
 		err = AudioUnitSetProperty (_au,
-		                            19 /*kAudioUnitProperty_SpatializationAlgorithm*/,
+		                            3000 /*kAudioUnitProperty_SpatializationAlgorithm*/,
 		                            kAudioUnitScope_Input,
 		                            0,
 		                            &renderingAlgorithm,